【摘要】 针对传统电磁超声全向导波换能器因导波内、外辐射致使检测回波信号复杂及信噪比低的问题，设计了一种新型电磁超声全向导波换能器(OUT-EMAT)结构，研究了换能器双线圈结构参数、双激励源控制方法，实现了导波辐射强度与方向控制。根据电磁超声全向换能器理论，建立波动位移叠加的数学模型，并对设计的OUT-EMAT性能进行仿真计算及实验。研究结果表明：与传统全向EMAT相比，OUT-EMAT内、外辐射导波强度之比由1∶1变为2∶9;其外辐射导波强度增加了100%,内辐射导波强度抑制了55.6%;增强了检测回波信噪比，降低了信号复杂度，提高了裂纹缺陷定位准确度；为有效识别裂纹缺陷提供了一种新方法，对实际工程应用具有指导意义。更多还原

【Abstract】 To solve the problem of complex echo signal and low signal-to-noise ratio caused by internal and external radiation of guided wave in the traditional electromagnetic ultrasonic omnidirectional guided wave transducer, a novel electromagnetic ultrasonic omnidirectional guided wave transducer(OUT-EMAT) is designed. The control method of double coil parameters and double excitation source is studied. The intensity and direction of guided wave radiation are controlled. According to the theory of the electromagnetic ultrasonic omnidirectional transducer, the mathematical model of wave displacement superposition is formulated, and the performance of OUT-EMAT is simulated and tested. Compared with the traditional omnidirectional EMAT, Simulation results show that the OUT-EMAT makes the ratio of internal and external radiation guided wave amplitudes change from 1∶ 1 to 2∶ 9. The external radiation is enhanced about 100% and the internal radiation is suppressed about 55.6%. The new OUT-EMAT enhances the signal to noise ratio of detection echo, reduces the complexity of signal and improves the accuracy of crack location. It provides a new method for identifying crack defect effectively, which has guiding significance for practical engineering application.更多还原